Implantable devices that monitor cardiac physiologic activity are frequently implanted subcutaneously under a patient's skin of the chest. An implantable loop recorder is an example of a device that may be implanted in this fashion. The implanted device may be leadless or may include subcutaneous leads. Two such devices are leadless and have a rigid rectangular shape. Another device, the Sleuth, is shaped like a small pacemaker, and includes a flexible lead extending from a header of the device. FIG. 1 shows an example of the Sleuth device. These devices can be used to record an electrocardiogram (EGG) signal for the patient.
To implant the Sleuth device, a 25 mm incision is made, a subcutaneous pocket is formed near the incision, and a tunnel is formed to extend away from the pocket for placement of the flexible lead using a tool or finger. The device may be inserted through the incision and placed in the subcutaneous pocket, tested for proper operation, and repositioned if necessary. The incision is then closed.
Implanting leaded devices in this manner may be difficult, especially for physicians who are not skilled in device implantation. If the device is improperly implanted, undesirable complications for the patient or suboptimal device performance may result. In addition, tearing of tissue during formation of the pocket and tunnel, for example, may result in tissue bleeding that requires appropriate steps during surgery to avoid hematoma. In addition, it may be necessary to employ fluoroscopy to assure that the flexible lead is properly positioned under the skin. If not properly positioned, the lead may require repositioning to obtain an optimal EGG signal. This may extend the surgery duration, which may increase risk of infection and trauma, as well as expense. A need exists for an improved device shape and associated insertion system for a simpler approach to insertion, shorter insertion time, reduced risk of complications, reduced expense, and a reduced need for expensive equipment, such as fluoroscopy, during device placement.